This is a National Phase of PCT/DE97/00838 filed Jul. 2, 1997 and based, in turn, on a German Application DE 19616.609.8 filed Apr. 4, 1996.
The invention relates to a trocar mandrel with a tip which permits piercing, of the abdominal wall, and hence an insertion into the abdominal cavity.
Such trocar mandrels, which are occasionally referred to as trocars only, are used, for instance, to create an artificial access through the abdominal wall into the abdominal cavity, which is suitable for laparoscopy.
In laparoscopic operations the trocar mandrel is introduced into a trocar shaft, which is sometimes referred to as trocar sleeve or simply trocar only. The trocar mandrel with the surrounding trocar shaft is forced through the abdominal wall. When the insertion is completed the trocar mandrel is drawn out from the trocar shaft so that other instruments such as an endoscope, forceps, scissors and/or similar devices may be inserted into the passage of the trocar shaft.
In certain operation techniques a specific needle is introduced prior to the insertion of the trocar into the abdominal wall, which is used for insufflation of the abdominal cavity with a gas, e.g. CO2 in particular.
One example of such a needle is the needle known as xe2x80x9cVeress needlexe2x80x9d, which has normally a diameter of 2.4 mm. After the xe2x80x9cinsufflation of the abdominal cavity with an insufflation gas, i.e. following the creation of overpressure of up to 50 Torr, the trocar mandrel with the trocar shaft is introduced through another xe2x80x9cpuncturexe2x80x9d or after withdrawal of the Veress needle through the same puncture. In laparoscopic operations the trocar mandrel has a typical diameter of 10 mm.
During the introduction of the trocar mandrel unintended damage may occur in the abdominal cavity; moreover, it may be that the tip of the trocar mandrel is not properly inserted into the abdominal cavity proper.
In the U.S. Pat. No. 5,407,427, discloses a trocar mandrel with a tip which permits the piercing through the abdominal wall. An insufflation passage is provided in the trocar mandrel, which extends along the direction of the longitudinal axis of the trocar mandrel, with the axis and hence the distal discharge opening of the passage being spaced from the tip by a distance in the direction orthogonal on the longitudinal axis of the mandrel which presents an axially symmetrical design in all other respects.
That known trocar mandrel makes it possible to dispense with the use of a Veress needle (cf. the passage from line 51 onwards in column 9 of the U.S. Pat. No. 5,407,427).
There is the disadvantage, however, that while the abdominal wall is pierced the situation may occur that the discharge opening is xe2x80x9ccloggedxe2x80x9d with tissue so that it is no longerxe2x80x94or only insufficientlyxe2x80x94possible to insufflate a cavity such as the abdominal cavity.
The present invention is based on the problem of improving a trocar mandrel as shown by the U.S. Pat. No. 5,407,427 in such a way that the occurrence of complications, especially as a result of clogging of the insufflation passage in the trocar mandrel, will be prevented whilst it is still possible to dispense with the use of a Veress needle during insertion of the trocar.
In accordance with the present invention in insufflation needle is arranged for displacement in the insufflation passage, which needle comprises a laterally disposed opening for the discharge of the insufflation fluid.
The inventive trocar mandrel can be used in the common manner to create a direct access, e.g. into the abdominal cavity, with the occurrence of complications being precluded which may result from an inappropriate insertion procedure or a lesion caused by the insufflation needle. The arrangement of the discharge opening for the insufflation fluid and particularly the gas on the side of the insufflation needle reliably prevents the clogging of the discharge opening and hence the insufflation access with tissue when the abdominal wall is pierced through. This provision ensures that the insufflation process may be started in a trouble-free manner immediately after the piercing of the abdominal wall.
In an improvement the distal end of the insufflation needle is pointless. On account of the pointless configuration of the distal end of the insufflation needle it is not possible that a tip existing on the insufflation needle will provoke lesions in the abdominal cavity after the abdominal wall has been pierced through.
In any case, the trocar mandrel is still suitable for use in the common manner due to the offset arrangement of the tip and the passage.
The inventive instrument, which combines an insufflation needle such as a Veress needle with a trocar mandrel in one and the same instrument, permits the creation of a direct access to the abdominal cavity so that the undesirable incidences or complications, which may occur when the instruments are used separately, can no longer occur and are at least reduced if not completely avoided.
In the further improvement the distal end of the insufflation needle projects beyond the tip of the trocar mandrel in the normal case. As the insufflation needle is supported for displacement in opposition to a resilient force for sliding back behind the tip, the insufflation needle is pushed back behind the xe2x80x9cengagement surfacexe2x80x9d of the mandrel when the abdominal wall is pierced through. As a result not only an easy piercing through the abdominal wall is ensured but the needle is also protected from damage etc.
The trocar mandrel may present the external shape of a trocar mandrel known per se and may present a conically scarfed tip in particular. In another preferred embodiment the tip may present at least two slopes which form cutting edges. In this design the discharge opening of the insufflation passage may be provided in one of the slopes.
On account of the inventive combination of a Veress needle and a trocar in a single instrument it is moreover possible that the diameter of the insufflation passage and hence of the insufflation needle is larger than the diameter of bore of conventional Veress needles. In particular, the diameter may be roughly 3 mm and more.
It is yet possible to provide (at least) one additional flushing passage in the trocar mandrel for the supply and/or evacuation of a wash fluid, such as a liquid.
The inventive trocar mandrel may, of course, be designed as a disposable trocar. It is preferred, however, that it is suitable for sterilisation for multiple application, and in particular it is configured for being dismantled for sterilisation. This dismantling ensures that cavities etc. can be reliably sterilised, too.